Silica gel is a core substrate for creating functionalized surfaces for separation sciences. Additionally, silica enables and enhances the chemical and thermal stability of the ligands attached to its surface. [Bermudez, V. Z., et al., 1999. Chem. Mater. 11, 569; Prado. A. G. S., Miranda, B. S., Dias, J. A. 2004. Colloids and Surface A: Physlcochem. Eng. Aspects, 242, 137.] The active silanol groups on silica gel surface can react with organosilyl groups which contain the desired functional groups. This creates a variety of inorganic—organic hybrid surfaces which exhibit practical advantages such as structural stability, swelling behavior, thermal properties, accessibility of reactive centers, and insolubility in water and organic solvents. These hybrids have been widely applied in heterogeneous catalysis, metal ion and pesticide preconcentration, ion exchange, separation of metal ions, stationary phases for chromatography, biotechnology, and in controlled release pesticides.
Silica is also a very important dielectric material, which has been widely used as a gate insulator and an interlayer insulator between metal wiring layers of semi-conductor or thin-film transistor displays and other related applications. [Saito, K., et al. 2003, Thin Solid Films, 430, 287.] Furthermore, with the embedding of metal nano-particles (e.g., Ag, Cu), the potential applications of Si02 as an insulator in non-linear optical systems are attractive for future ultrafast networks and circuits ahead of semiconductor devices. [Takeda. Y., Kishimoto, N., 2003 Nucl. Instr. Meth. B, 206, 620.]
Recent technological advances in silicon processing allow small-scale fabrication of high-speed devices. As the size of the silicon device is scaled down, the device performance is limited by the fabrication processes of the gate structure. Therefore, a totally low-temperature process for the gate dielectric formation and post-gate process with no degradation of the fine doping profile or the gate stack is important for Si device fabrication. [Nishizawa, J., Kurabayashi, T., Kanamoto, K., Yoshida, T., and Oizumi, T., 2003. Mater. Sci. Semicond. Process, 6, 363.] However, current methods to synthesize/generate Si02 thin films have many disadvantages including (1) that the methods are time consuming, (2) the need for complex instrumentation, (3) the requirement for catalysts and (4) the harsh working conditions such as high temperature, argon environments [He, L. N and Xu, J., 2003 Vacuum, 68, 197] and operation under vacuum. In addition, some of the approaches can cause oxygen-originated damage due to use of plasma. We have developed a quick and simple method to make patterned Si02/Ti02 thin films through convenient photo and chemical reactions under ambient atmosphere and room temperature. The cost is low and the process approach is environmentally benign.